(Last edited: Saturday, 24 February 2024, 1:51 PM)
Answer:
Sometimes they are dangerous, but sometimes they are not. There are dangerous bacteria, which make you sick, and useful bacteria, which make your life easier. For example, chlamydiae are bacteria that cause painful urination and vaginal symptoms. But, other useful bacteria help fermentation and make fermented food such as yogurt, kunelaoto, uji, beer, and so on.